This invention relates to attachments for milling machines, specifically to a variable speed milling machine attachment, and a method for its use, that is efficiently configured for minimal reduction of the spindle-to-table workspace of a milling machine, such as the well-known Bridgeport miller, and which when attached to a milling machine having a maximum spindle speed of approximately 5,000 rpm, allows an operator to perform high speed milling, grinding, drilling, and engraving functions at selected sustained spindle speeds greater than 5,000 rpm, up to and including sustained spindle speeds above 20,000 rpm.